Currently, 29 states have enacted legislation providing for the installation of alcohol safety interlocks on the vehicles of offenders convicted of driving under the influence (DUI) by courts or the Motor Vehicle Department. This device requires a breath sample from the operator prior to staring the vehicle and prevents ignition if there is a significant amount of alcohol (.02 or greater) in the driver's breath. These programs are gaining popularity because they appear to be a method of reducing the crash involvement of the high risk DUI drivers while not interfering with the offenders job-related driving. To date, interlock programs have been implemented solely to reduce alcohol related crash involvement of DUI offenders. The potential of these programs for reducing other drinking related problems has not been explored. This study is designed to produce an effective intervention program for multiple DUI offenders which can be implemented while their elevated alcohol related crash risk is controlled by the ignition interlock. It will put in place a unique case management system (in one of two locations) in a relapse prevention context. Case managers will have available a wide range of free health and social services based on the readiness of the client to accept change. Indications of client behavior will come from monthly interviews and data read from the interlock data logger. The services will include employment assistance, vocational training, fly counseling, and alcohol and drug abuse programs as well as medical treatment. The effectiveness of health services linkages provided as an adjunct to the interlock program in reducing, drinking problems and preventing relapse will be evaluated. This research will take advantage of an opportunity provided by recent legislation in the Province of Alberta to conduct two studies: one on the effectiveness of the interlocks in preventing crash involvement and DUI recidivism among first offenders and a second study directed at evaluating the potential of the interlock for providing health services to multiple DUI offenders required to place interlocks on their vehicles. This study will be conducted in Alberta, Canada because their legislation requires installation of an interlock for a modal 12 months on the vehicle of every multiple offender seeking reinstatement, and also provides for placing the unit for 6 mo. on as many first offender cars as can be accommodated by the manufacturer. Since, not all first offenders can be accommodated, units will be provided on the basis of a lottery which will insure random assignment among the 1,500 first offenders who are expected to request participation in the program. Strong reliable administration of the program is assured by assignment of responsibility to a single provincial agency, the Driver Control Board, which has fall power over the reinstatement of convicted DUIs.